# (no subject)

Dear lammps users

I want to calculate the total energy of an isolated atom, Please can anyone help me ?
Best regards

just make a per atom variable that adds a pe/atom compute to a ke/atom compute.

Dear lammps users

I want to calculate the total energy of an isolated atom, Please can
anyone help me ?

​pick any number you want. absolute energies have no meaning in classical
models, only energy differences.

​axel.​

​p.s.: ​ ​if you ask a more specific questions with more/better context, we
may be able to give a more specific and better answer....​

just make a per atom variable that adds a pe/atom compute to a ke/atom
compute.

​why use the computer, when you can answer this with a little bit of
thinking?​

​i.e. ​for an *isolated* atom, you can just pick zero. the system is
invariant to translation and the atom has nothing to interact with (it is
isolated). any kind of "internal energy" is not represented with a
classical model, anyway.

axel.​

I want to calculate the adsorption energy for Cu adsorbed atom on Pt(100) surface. I use this formula: Eads= E(ad+slab) - Eslab, where E(ad+slab) is the total energy of Pt surface with adsorbed Cu atom, and Eslab is the energy of the Pt(100) surface without the adsobed Cu atom. I’v got a large adsorption energy (in the order of 200 eV). It looks that something wrong, Please I need your help.
For this reason, I use another formula to calculate the adsorption energy that is: Eads= E(ad+slab) - Eslab - Eatom. Eatom is the energy of an isolated atom. So how can I calculate the energy of an isolated atom? or if there is another way for the calculation of the adsorption energy for this system Cu/Pt(100).

Best regards

As was answered, take a look at compute pe/atom

and compute ke/atom. They can calculate the energy

of any atom you wish.

Steve